Diazo condensation polymers



United States Patent Ofiice 3,050,502

Patented Aug. 21, 1962 l 2 3 050 502 vide an improved process for the preparation of diazo DIAZO coNnniusrtrrou roLYMERs l lbert Mellan, Bayside, N.Y., assi nor to Polychrome Cor- A mailer Oblect of h mstam mvwnon is to pmvlde poration, Yonkers, N.Y., a corporation of New York novel dlaZP condensauon Polymer- No Drawing. Filed Jan. 29, 1959, Ser. No. 789,782 5 Other ob ects and the advantages of the instant inven- 5 Claims. (Cl. 260-725) tion will become apparent in the description which follows. The instant invention relates to an improved method for The diazo condensation polymers of the instant inventhe preparation of high molecular weight diazo comtion are formed according to the following formula sepound-s. More particularly the instant invention relates quence:

ll ll 0 O ZlJClz Z1101; 2 2

to a procedure for the preparation of high molecular The first step in the process is to convert para-amino weight photosensitive diazo compounds and to the novel diphenyl amine to the double salt of Zinc chloride para compounds termed thereby. Such compounds have found diazo nit-roso diphenyl by reaction with sodium nitrite in particular utility in pro-sensitized lithographing plates. a sulfuric or hydrochloric acid medium (nitrous acid).

In some diazo reproduction roce e diazonium oom- This reaction is efiected at temperatures below about pounds of lugh molecular weight are desirable or e e 10 C., and the reactant solution should be protected from F example, it has been found that the photo delight. Thereafter the diazo nitroso compound is salted composition products of certain high molecular weight i of lution as the Zinc chloride Salt. diazo compounds are ne e ary i the onver i n f By and large conventional diazotization temperature lected natural or synthetic materials of colloidal nature nd acid c condit ons and overall techniques are employed from hydrophilic water soluble materials to water repelfor forming the diazo nitroso compound. However, since lent form. Thus, in a lithographing plate a hydrophilic the nitroso derivative is desired, the nitrite should be used coating thereon is treated with a light sensitive diazo COll'l- 40 in a 2:1 molar ratio relative to the para amino diphenyl pound and exposed to ultra vio-let light through a negative amin therehy rendering the exposed portions hydrophilic and The unusual stability of this diazo nitroso derivative ink receptive. permits the subsequent condensation with formaldehyde It has been suggested to prepare such high molecular and rearrangement shown by the above formula sequence weight diazo compounds by condensation of relatively low to occur in the Tange of ambient temperature to about molecular weight diazonium compounds with aldehydes 70 C., a relatively elevated temperature for this type of and/ or ketones. As is well known in the art, aromatic Condensation. hydrocarbons and certain derivatives .theregf which in- The actual condensation and rearrangement i5 eifected clude the diazonium compounds, react with carbonyl comin a moderately Concentrated Sulfuric acid medium pounds, notably tormaldehyde, to form a wide variety of in the Iangfi of about With a 111 1110i ratio 0f high molecular Weight products. Initially the aromatic for lde yde to diazo compound. The formaldehyde hydrocarbon reacts with one moleculare of formaldehyde may s it bly e in "the form of paraformaldehyde, trito form a methylol derivative. The last then condenses OXflne fOTmfiiiIl, Or other Wathl" Solublh aldehydhs, with a second molecule of the aromatic with the eliminaerally thOSe Containing not m an 3 Car n tomstion of water to form a methylene bridge when the aro- The condensation product which is precipitated out of matic hydrocarbon possesses two or more reactive hysolution by the addition of salt and zinc chloride has a drogens. Theoretically such an aromatic material can g d gree of thermal stability yet retains the light sen- .condense i h an equi-molar quantity f formaldehyde sitivity desired indiazo compounds, particularly as they to produce condensation polymers of extremely high m0- may be used in connection with presensitized metal litholecular weight. As recognized by the art, thediazonium 6O graphing plates, e.g. see copending application Serial No. compounds and formaldehyde will condense in accordance 403,291, Owned by applicants assignee.

with the above mechanism to give high molecular weight For further understanding of the invention the followpolmers. However, since the diazonium compounds are ing examples are presented.

more or less thermally unstable, low temperatures must EXAMPLE I be employed for the condensation, necessitating refrigeration to maintain the reacting mixture at below about Add grams of P amino diphenyla'mine to 1,000 10 C. for the extended period of time the condensation Wamr containing 32 Concentrated y reaction requires. Considering that the diazonium comchlolic acid H631 to abflllt C- pounds are also quite light sensitive, the requirement for and m at this temphl'ahlre until 3411 the R amino l refirigeration further complicates processing conditions and 70 Phhnylamine dissolved- C001 1116 Tesultlng Solution 10 adds sharply to the expense of the ultimate product. 3 C.-5 C. From this point on, the solutions and the The principal object of the instant invention is to prosynthesis must be protected from light.

The next step in the process is to dissolve 12 grams of sodium nitrite in 50 cc. of cold water at C. and add this to the solution of para amino diphenylamine hydrochloride, all at once, and stir constantly for -15 minutes. Filter the resulting solution and begin to salt out the para diazo nitroso diphenyl as soon as possible.

Add 100 grams of salt (NaCl) to the filtrate with con stant stirring, then add 100 cc. of a solution containing 10 grams of zinc chloride, and finally add about 200 grams of salt, in small quantities, or enough salt to complete the precipitation.

The precipitate is removed by filtration and then Washed free of both hydrochloric acid and the slight excess of nitrous acid with a saturated solution of sodium chloride containing 5 percent of Zinc chloride. To obtain this compound in a dry form, drain as much liquid as possible from the filter cake and dry the compound under vacuum, carefully protected from light. The moist paste is now ready for the second phase of the synthesis.

Condensation and Rearrangement Disperse the moist filter cake in 90 cc. of cold water. Add 150 cc. of concentrated sulfuric acid (66 as. in 5 cc. portions, and stir constantly. Care must be taken not to permit the temperature to rise above 70 C. Should the temperature rise above 70 C., then stop adding the acid until the temperature drops down below 70 C. When all the acid has been used, add 3 grams of trioxymethylene, and permit the mixture to stand at room temperature of 4 to 5 hours.

Slowly pour this mix-ture on 1,000 grams of ice. Stir until the ice melts; dilute with water to 2,000 cc.; and filter. To the filtrate add 100 grams of sodium chloride and 100 cc. of 10 percent zinc chloride solution, then add more sodium chloride until precipitation is complete. Remove the precipitate by filtration and Wash with saturated sodium chloride solution containing 5 percent of Zinc chloride w./v., drain and dry under vacuum in a dark chamber.

Another method of condensation is as follows:

Slowly add 100 cc. of concentrated sulfuric acid (66 B6.) to 90 cc. of cold water. Cool the resulting solution to 70 C. Add small amounts of the para diazo nitroso diphenyl filter cake to the hot sulfuric acid solution and stir constantly. Care must be taken not to allow the reaction to become too violent or to allow the temperature to go above 70 C. When half of the filter cake is added and the solution begins to thicken, add an additional 50 cc. of sulfuric acid (66 Be.) in 25 cc. portions. The temperature is not permitted to rise above 70 C. Continue to add small pieces of the filter cake until it is all consumed. Add 3 grams of trioxy-methylene. Permit the reaction mixture to remain for 4 to 5 hours, then slowly pour this mixture upon 1,000 grams of ice, and stir. When the ice has melted, dilute this solution to 2,000 cc. Permit the solution to stand for several hours in order to make certain that solution is complete; then filter. To the filtrate add 100 grams of salt, 100 cc. of 10 percent zinc chloride solution (w./v.) and finally enough sodium chloride to complete precipitation, all with constant stirring. Filter and wash the precipitate with saturated sodium chloride solution containing 5 percent of zinc chloride (w./v.). Dry in a dark place under vacuum.

In order to prepare a dry product, free of impurities, the following procedure has been developed. About 300 grams of wet filter cake are suspended in 1,000 cc. of methyl alcohol, filtered, and the residue is again suspended in 1,000 cc. of methyl alcohol. The purified product is then removed by filtration, air dried, and stored in a dry place protected from light.

in the foregoing, this invention has been described only in connection with preferred embodiments thereof. Many variations and modifications of the principles of the present invention within the scope of the description herein are obvious. Accordingly, it is preferred to be bound not by the specific disclosure herein, but only by the appending claims.

I claim:

1. A condensation process which comprises contacting the double zinc chloride salt of para diazo nitroso diphenyl with formaldehyde in admixture with sulfuric acid and at a temperature in the range of about ambient temperature to C.; and thereafter recovering the condensation product from the sulfuric acid solution.

2. The process of claim 1 in which the condensation product is dried and purified by contacting same with methyl alcohol, filtered and dried.

3. A process for preparing high molecular weight light sensitive materials which comprises diazotizing para amino diphenylamine by contact with at least two moles of sodium nitrite in an acid medium whereby para diazo nitroso diphenyl is formed; precipitating out the Zinc chloride salt of the para diazo nitroso diphenyl; thereafter dissolving the salt in sulfuric acid and contacting same with a Water-soluble aldehyde having not more than 3 carbon atoms at a temperature in the range of ambient temperature to about 70 C. and recovering the resulting condensation product from the sulfuric acid solution.

4. A process for preparing high molecular weight light sensitive materials which comprises diazotizing para amino diphenylamine by contact with at least two moles of sodium nitrite in an acid medium whereby para diazo nitroso diphcnyl is formed; precipitating out the zinc chloride salt of the para diazo nitroso diphenyl; thereafter dissolving the salt in sulfuric acid and contacting same with about one mole of formaldehyde at a temperature in the range of ambient temperature to about 70 C.; and recovering the resulting condensation product from the sulfuric acid solution.

5. The process of claim 4 wherein the sulfuric acid solution employed for dissolving the zinc chloride salt has a density of about 1.4-1.6.

OTHER REFERENCES Degering: An. Outline of Organic Nitrogen Compounds, University Lithoprints, Michigan, 1950, p. 302. 

1. A CONDENSATION PROCESS WHICH COMPRISES CONTACTING THE DOUBLE ZINC CHLORIDE SALT OF PARA DIAZO NITROSO DIPHENYL WITH FORMALDEHYDE IN ADMIXTURE WITH SULFURIC ACID AND AT A TEMPERATURE IN THE RANGE OF ABOUT AMBIENT TEMPERATURE TO 70*C.; AND THEREAFTER RECOVERING THE CONDENSATION PRODUCT FROM THE SULFURIC ACID SOLUTION. 